Generally, display devices such as thin film transistor (TFT) liquid crystal display devices or organic EL devices have an electrode overcoating, a planarization film, an insulation film and the like forming a pattern. As materials to form such films, a photosensitive resin composition is widely used, which requires only a small number of process steps to form a desired pattern and has such a characteristic as a sufficient planarization property. Further, such films are required to have various properties including process resistance such as heat resistance, solvent resistance or long-time baking resistance, high transparency and adhesion to substrates.
Therefore, positive photosensitive resin compositions to form such films are required to give cured materials excellent in the above properties. Further, in addition, it is desired that the photosensitive resin compositions have good storage stability and a wide process margin so that patterns can be formed under various process conditions suitable for the particular purposes. Further, photosensitive properties such as resolution and sensitivity are also important. On the other hand, for the liquid crystal display devices, it is also essential to use materials having such high reliability that, for example, they will not contaminate liquid crystal.
Thus, various properties are required for photosensitive resin compositions for display materials. Therefore, with respect to respective properties of the photosensitive resin compositions, various studies have been conducted heretofore. For example, as one satisfying both high heat resistance and high transparency, a material having glycidyl groups in an alkali-soluble resin has been reported (JP-A-8-262709). On the other hand, as one realizing high sensitivity and high resolution, a material employing a 1,2-naphthoquinone diazide compound has been reported (JP-A-4-211255).
However, it is not necessarily easy to develop a photosensitive resin compound which can satisfy all of the above various properties, and a mere combination of prior arts has been hardly successful. Further, up to now, there has been no case that reports on a highly reliable material not to deteriorate electrical characteristics in its application for liquid crystal display devices.